Actualización en espirometría y curva flujo / volumen en escolares y adolescentes / School and adolescent spirometry and flow / volume curve update

Spirometry is the most commonly used test to evaluate lung function in children and adults. To obtain good quality results, several requirements must be fulfilled: professional capacity of the technician, the quality of the equipment, the patient's collaboration, the use of appropriate reference standards. The purpose of spirometry is to define types of ventilatory alterations of the central and peripheral airways, to evaluate the response to bronchodilators and to guide the presence of restrictive diseases. The new consensus of national and international experts are described, which have been perfecting several aspects of this test.

La espirometría es el examen más comúnmente utilizado para evaluar la función pulmonar en niños y adultos. Para obtener resultados de buena calidad deben cumplirse varios requisitos, desde la capacidad profesional del técnico, calidad de los equipos, colaboración del paciente y utilización de patrones de referencia adecuados. La espirometría tiene como utilidad definir alteraciones ventilatorias obstructivas de vía aérea central y periférica, evaluar respuesta a broncodilatador y orientar al diagnóstico de enfermedades restrictivas. Se describen los nuevos consensos de expertos nacionales e internacionales, los cuales han ido perfeccionando varios aspectos de este examen.

Bronquiolitis obliterante secundaria a sindrome de stevens-johnson. Presentacion de 2 casos y revision de la literatura / Obliterans bronchiolitis secondary to stevens-johnson syndrome: case reports

Stevens-Johnson syndrome corresponds to a hypersensitivity reaction produced by various etiologies, for example exposure to drugs, microbial agents, or by an idiopathic cause. It is marked by an acute vesicular-bullous eruption, which affects the skin and mucous membranes, with systemic manifestations of variable severity, and it may present a fatal evolution. Stevens-Johnson syndrome can occasionally present chronic pulmonary complications, such as bronchiolitis obliterans; however, other etiologies are more frequent in our environment, for example severe pneumonia due to adenovirus. Our objective is to present two cases of bronchiolitis obliterans post Stevens-Johnson syndrome and to make a literature review.

El síndrome de Stevens-Johnson corresponde a una respuesta de hipersensibilidad producida por diversas etiologías, que incluyen exposición a drogas, agentes microbianos o idiopática. Se manifiesta por una erupción vesículo-bulosa aguda, que afecta la piel y las mucosas, con manifestaciones sistémicas de severidad variable, pudiendo presentar una evolución fatal. El síndrome de Stevens-Johnson puede presentar ocasionalmente complicaciones pulmonares crónicas, como bronquiolitis obliterante, siendo en nuestro medio más frecuente otras etiologías, como la observada luego de una neumonía grave por adenovirus. El objetivo es presentar dos casos de bronquiolitis obliterante post síndrome de Stevens-Johnson y hacer una revisión de la literatura.

Evaluación de flujos y volúmenes dinámicos en pacientes con compromiso muscular respiratorio / Dynamic flows and volumes evaluation in patients with respiratory muscle impairment

Spirometry measures the forced expiratory volumes and flows. In patients with neuromuscular disease, these are altered since there is some respiratory muscle involvement. The usefulness of this test is based on the interpretation of the shape of the flow / volume loop and values of spirometric variables. In patients with neuromuscular disease, Forced Vital Capacity is the most used especially for its prognosis value.

La espirometría mide volúmenes y flujos espiratorios forzados. En los pacientes con enfermedad neuromuscular (ENM) estos se ven alterados debido al compromiso muscular respiratorio. La utilidad de este examen se basa en la interpretación de la forma de la curva flujo/volumen y los valores de las variables espirométricas. En los pacientes con ENM la Capacidad Vital Forzada es la más utilizada ya que otorga valor pronóstico.

Quality control for maximal expiratory flow-volume curve as a pulmonary function test in school-age children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To assess the quality control for the maximal expiratory flow-volume (MEFV) curve in school-age children.</p><p><b>METHODS</b>Eight hundred and sixty-two children who had two or more MEFV manoeuvres were classified into ≥6-year-old (n=379), ≥8-year-old (n=210), ≥10-year-old (n=64), and 12-17-year-old groups (n=109). The parameters of quality control and concordance with quality control criteria for MEFV were compared between the two groups. In addition, patients who were diagnosed with asthma were classified into two groups, one with normal pulmonary function (n=155) and the other with abnormal pulmonary function (n=62), based on the results of spirometry. Differences in the parameters of quality control for spirometry were compared between the two groups.</p><p><b>RESULTS</b>Eight hundred and sixty-two children underwent 2 367 MEFV manoeuvres, 97.8% of which met the start of test criterion for backward extrapolated volume (VBE) of less than 0.15 L, with the highest concordance in the ≥6-year-old group and the lowest concordance in the 12-17-year-old group. Three hundred and eighty-one children (44.2%) met the end of test criterion for forced expiratory time (FET) and the concordance in children over 10 years of age was lower than that in children under 10 years of age (P<0.05). Differences in two best forced expiratory volume in first second (FEV1) and forced vital capacity (FVC) manoeuvres were within 150 mL in 91.9% and 84.8%, respectively, of the children. The parameters of quality control for spirometry were better for asthmatic children with abnormal pulmonary function compared with asthmatic children with normal pulmonary function (P<0.05).</p><p><b>CONCLUSIONS</b>Concordance with the start of test criteria and the manoeuvre repeatability criteria is high, whereas the concordance with the end of test criteria is low. It is suggested that the concordance with the FET criteria should be improved.</p>

Changes in the Flow-Volume Curve According to the Degree of Stenosis in Patients With Unilateral Main Bronchial Stenosis

OBJECTIVES: The shape of the flow-volume (F-V) curve is known to change to showing a prominent plateau as stenosis progresses in patients with tracheal stenosis. However, no study has evaluated changes in the F-V curve according to the degree of bronchial stenosis in patients with unilateral main bronchial stenosis. METHODS: We performed an analysis of F-V curves in 29 patients with unilateral bronchial stenosis with the aid of a graphic digitizer between January 2005 and December 2011. RESULTS: The primary diseases causing unilateral main bronchial stenosis were endobronchial tuberculosis (86%), followed by benign bronchial tumor (10%), and carcinoid (3%). All unilateral main bronchial stenoses were classified into one of five grades (I, 90% to near-complete obstruction without ipsilateral lung collapse). A monophasic F-V curve was observed in patients with grade I stenosis and biphasic curves were observed for grade II-IV stenosis. Both monophasic (81%) and biphasic shapes (18%) were observed in grade V stenosis. After standardization of the biphasic shape of the F-V curve, the breakpoints of the biphasic curve moved in the direction of high volume (x-axis) and low flow (y-axis) according to the progression of stenosis. CONCLUSION: In unilateral bronchial stenosis, a biphasic F-V curve appeared when bronchial stenosis was >25% and disappeared when obstruction was near complete. In addition, the breakpoint moved in the direction of high volume and low flow with the progression of stenosis.

Oxygen desaturation during the six-minute walk test in COPD patients / Análise da dessaturação de oxigênio durante o teste de caminhada de seis minutos em pacientes com DPOC

Objective: To evaluate the behavior of oxygen saturation curves throughout the six-minute walk test (6MWT) in patients with COPD. Methods: We included 85 patients, all of whom underwent spirometry and were classified as having moderate COPD (modCOPD, n = 30) or severe COPD (sevCOPD, n = 55). All of the patients performed a 6MWT, in a 27-m corridor with continuous SpO2 and HR monitoring by telemetry. We studied the SpO2 curves in order to determine the time to a 4% decrease in SpO2, the time to the minimum SpO2 (Tmin), and the post-6MWT time to return to the initial SpO2, the last designated recovery time (RT). For each of those curves, we calculated the slope. Results: The mean age in the modCOPD and sevCOPD groups was 66 ± 10 years and 62 ± 11 years, respectively. At baseline, SpO2 was > 94% in all of the patients; none received supplemental oxygen during the 6MWT; and none of the tests were interrupted. The six-minute walk distance did not differ significantly between the groups. The SpO2 values were lowest in the sevCOPD group. There was no difference between the groups regarding RT. In 71% and 63% of the sevCOPD and modCOPD group patients, respectively, a ≥ 4% decrease in SpO2 occurred within the first minute. We found that FEV1% correlated significantly with the ΔSpO2 (r = −0.398; p < 0.001), Tmin (r = −0.449; p < 0.001), and minimum SpO2 (r = 0.356; p < 0.005). Conclusions: In the sevCOPD group, in comparison with the modCOPD group, SpO2 was lower and the Tmin was greater, suggesting a worse prognosis in the former. .

Objetivo: Avaliar o comportamento da curva de saturação de oxigênio durante o teste de caminhada de seis minutos (TC6) em pacientes com DPOC. Métodos: Incluímos 85 pacientes e todos realizaram espirometria, sendo classificados como portadores de DPOC moderada (DPOCm, n = 30) ou grave (DPOCg, n = 55). Todos os pacientes realizaram TC6 em um corredor de 27 m com monitoramento contínuo da SpO2 e FC por telemetria. A partir das curvas de SpO2, foram analisados os tempos para atingir a queda de 4% da SpO2, para atingir a SpO2 mínima (Tmin) e para a recuperação da SpO2 após o TC6 (TR). Foram calculadas as inclinações dessas curvas. Resultados: A média de idade nos grupos DPOCm e DPOCg foi de 62 ± 11 anos e 66 ± 10 anos, respectivamente. Todos os pacientes iniciaram o teste com SpO2 > 94%, nenhum recebeu suplementação de oxigênio durante o TC6, e não houve interrupções. A distância percorrida no TC6 não apresentou diferença significativa entre os grupos. Os menores valores da SpO2 ocorreram no grupo DPOCg. Não houve diferença no TR entre os grupos, e 71% e 63% dos pacientes nos grupos DPOCg e DPOCm, respectivamente, apresentaram queda de SpO2 ≥ 4% até o primeiro minuto. O VEF1% apresentou correlações significativas com ΔSpO2 (r = −0,398; p < 0,001), Tmin (r = −0,449; p < 0,001) e SpO2 mínima (r = 0,356; p < 0,005). Conclusões: As curvas dos pacientes do grupo DPOCg em relação às do grupo DPOCm apresentaram valores menores de SpO2 e maior Tmin, sugerindo um pior prognóstico nos primeiros. .

Fisiología de la curva flujo/volumen espirométrica / Flow-volume curve: its physiological basis

We describe physiological basis to explain flow/volume curve obtained by forced spirometry. The main factors involved are alveolar and intraluminal airway pressure and transthoracic pressure, whose interrelationship determines dynamic airway compression. Lung and thoracic elastic recoil pressure and lung volumes also participate.

Se describen las bases fisiológicas de la curva flujo/volumen obtenida mediante espirometría forzada. Los principales factores involucrados son la presión alveolar y de la vía aérea y la presión transtorácica, cuyo balance determina la compresión dinámica de la vía aérea. Además intervienen la presión de retracción elástica pulmonar y de la caja torácica y los volúmenes pulmonares.

Spectral analysis of respiratory flow and gas concentrations / Análise espectral de fluxo e concentrações de gases respiratórios

In this research we obtained samples of human respiratory flow, oxygen concentration and carbon dioxide concentration signals from 20 healthy subjects and evaluated the average power spectral density (PSD) of these signals. For each subject,the respiratory samples were acquired in four progressive levels of exercise in a cycle ergometer. Auto regressive moving average models were designed to represent the PSD found in each phase. An average PSD of the four levels was also calculated. Results have shown that the bandwidth of O2 concentration, CO2 concentration and flow signals was 8  Hz, 7 Hz, and 15  Hz, respectively, within the dynamic range of 50  dB. The PSD curves found can be used for optimal filter design for signal enhancing in fast on-line measurement of these signals.

Nesta pesquisa foram registradas amostras dos sinais respiratórios de fluxo, concentração de oxigênio e concentração de gás carbônico em 20 voluntários saudáveis. A densidade espectral de potência (DEP) média foi então calculada. Para cada voluntário, as amostras dos sinais foram registradas em quatro intensidades progressivas de esforço físico em uma bicicleta ergométrica. Para representar a DEP encontrada em cada fase foram ajustados modelos auto-regressivos de média móvel. Uma DEP média entre as quatro intensidades também é fornecida. Os resultados mostraram que as larguras de banda dos sinais de concentração de O2, concentração de CO2 e fluxo foram 8  Hz, 7  Hz e 15  Hz, respectivamente, dentro de uma faixa dinâmica de 50  dB. As curvas de DEP encontradas podem ser usadas em projetos de filtros ótimos para equalização destes sinais em medições em tempo real.

Pruebas de función pulmonar en el niño / Pulmonary function test in children

Contar con pruebas de función pulmonar permite realizar un diagnóstico y seguimiento más adecuado en los pacientes que presentan patología respiratoria crónica o recurrente, o en aquellos que padezcan una enfermedad que de forma directa o indirecta afecte al aparato respiratorio. Estos exámenes se pueden hacer en forma aceptable y reproducible en niños desde los tres a seis años de vida. En este artículo se detallan las características más importantes de las pruebas de función pulmonar que frecuentemente se utilizan en el niño, como son la espirometría, curva flujo-volumen, prueba de provocación bronquial con ejercicio y con metacolina y la flujometría. También se detalla una técnica novedosa que permite medir la resistencia de la vía aérea, denominada oscilometría de impulso, de la cual se dispone en Clínica Las Condes y tiene la particularidad de requerir mínima cooperación por parte del paciente. Para el médico que solicita un examen de función pulmonar, es relevante conocer las condiciones de aceptabilidad, reproducibilidad e interpretación básicas, para que tenga un verdadero rol en el manejo de la patología respiratoria del niño.

Expression of thioredoxin-binding protein-2/vitamin D3 upregulated protein-1 in peripheral blood eosinophils of asthma patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of vitamin D3 upregulated protein-1 (VDUP1) in peripheral eosinophils at different stages of asthma and its correlation with clinical manifestations of asthma.</p><p><b>METHODS</b>Fourteen normal volunteers and 51 mild to moderate asthma patients, including 16 untreated patients with asthma attack and 35 with asthma remission by continuously corticosterone inhalation. The symptom severity and pulmonary function indices were evaluated and induced sputum eosinophil counts and blood eosinophil count measured. VDUP1 and beta-actin gene fragments were amplified simultaneously by RT-PCR from the total RNA of peripheral eosinophils, and 10 microl of the RT-PCR product underwent agarose gel electrophoresis and the VDUP1/beta-actin ratio was obtained by Gel-Pro software.</p><p><b>RESULTS</b>VDUP1/beta-actin ratio significantly decreased in untreated patients with asthma attacks in comparison with normal volunteers (0.314+/-0.242 vs 0.532 +/-0.279) but not in patients with asthma remission (0.612+/-0.381). In the former patients, a positive correlation of VDUP1/beta-actin ratio was found with FEV1.0% (r=0.587, P=0.046) and %PEF (r=0.563, P=0.033), whereas an inverse one observed with sputum eosinophil count (r=-0.436, P=0.049).</p><p><b>CONCLUSION</b>VDUP1 expression in the eosinophils correlates to eosinophil activation and may influence the disease severity of asthma patients.</p>

Espirometría forzada y curva flujo-volumen en pediatría / Forced spirometry and flow-volume curve in pediatrics

La espirometría forzada constituye la prueba de función pulmonar más usada en el estudio de las enfermedades respiratorias, en esta revisión se describen las condiciones técnicas que permiten su realización en forma adecuada para una interpretación precisa del estado funcional respiratorio, particularmente en pediatría. Este artículo incluye aspectos como la estandarización, parámetros para curvas volumen-tiempo y flujo-volumen, requisitos técnicos, e informe espirométrico.

Effect of body posture on dynamic lung functions in young non-obese Indian subjects.

Flow volume loop and its various indices can be used to diagnose UAO. Change in posture from sitting to horizontal position per se causes a decrease in effort dependent inspiratory and expiratory flow rates but no significant change in upper airway obstruction indices. Thus, measurement of FVL in supine posture may be used to detect UAO as it may be missed if spirometry is performed in sitting posture.

Maximal expiratory flow volume curve in quarry workers.

Maximal Expiratory Flow Volume (MEFV) curves were recorded with a computerized Spirometer (Med Spiror). Forced Vital Capacity (FVC), Forced Expiratory Volumes (FEV), mean and maximal flow rates were obtained in 25 quarry workers who were free from respiratory disorders and 20 healthy control subjects. All the functional values are lower in quarry workers than in the control subject, the largest reduction in quarry workers with a work duration of over 15 years, especially for FEF75. The effects are probably due to smoking rather than dust exposure.

An Evaluation of the Ventilatory Function in Shipyard Welders Using the Lifetime Cumulative Exposure to Welding Fumes / 대한산업의학회지

Objectives:This study was conducted to evaluate the ventilatory function in shipyard welders using the lifetime cumulative exposure to welding fumes. METHODS: Ventilatory function tests were performed on 241 male welders at one large shipyard,exposed to welding fumes for over five years,and was compared to 80 male control subjects. Ventilatory function indices, such as forced vital capacity(FVC), one-second forced expiratory volume(FEV 1), ratio of FEV 1 to FVC(FEV 1%), maximal mid-expiratory flow(MMF), peak expiratory flow rate(PEFR)and maximal expiratory flow at 50 and 75% of expired FVC(FEF50 and FEF75), were obtained by analyzing forced expiratory spirograms and maximal expiratory flow-volume curves that were simultaneously measured by an Impulse ocillometry(IOS)program in the standing position. RESULTS: FEF50 and FEF75 expressed as a percentage of the predicted values were significantly lower in the exposure group than in the controls, and the MMF tended to decrease.The means of all the ventilatory indices,expressed as percentage of the predicted values, were not significantly increased at the current exposure levels. The MMF, FEF50 and FEF75, expressed as a percentage of the predicted values, were significantly decreased with an increase in exposure duration.Only the FEF75 , expressed as a percentage of the predicted value, was significantly decreased with an increase in the cumulativeexposure to welding fumes(C1). The FEF75, expressed as a percentage of the predicted value, was significantly decreased with an increase in the cumulative exposure to welding fumes(C2). The above parameters were calculated to consider the current exposure level, exposure duration, application of the ventilatory system, production rate, personal protection evice, electrode and welding wire. The MMF and FEF50, expressed as a percentage of the predicted value, tended to decrease. The proportion of workers with abnormal MMF, FEF50 and FEF75 were significantly increased with an increase in the cumulative exposure to welding fumes(C2). CONCLUSIONS: These findings suggested that the MMF, FEF50 and FEF75 are sensitive and practical indices for the evaluation of the ventilatory function of workers exposed to welding fumes, when the lifetime cumulative exposure(C2) is considered as a factor affecting exposure.

Bases fundamentais da espirometria / The fundamental basis of the spirometry

Com o objetivo de reunir em unico texto, de forma resumida e pratica, todos os conteudos basicos e fundamentais da espirometria, buscou-se na literatura pertinente ao tema os elementos mais importantes sobre ele, a saber: aspectos historicos, principais objetivos e cuidados tecnicos, tipos de equipamentos e classificacao ou detalhamento e resultados tecnicos espirometricos. Dentro da abordagem classificatoria estabeleceu-se uma divisao entre espirometria simples ou convencional e a completa ou por analise de gases. Na espirometria convencional, por meio das tres manobras basicas de capacidade vital lenta, capacidade vital forcada e ventilacao voluntaria maxima, explorou-se os elementos mais comumente empregados para a obtencao dos volumes, das capacidades e dos fluxos pulmonares, com uma visao geral da interpretacao dos resultados espirometricos

Advantages of late expiratory relaxation during maximal forced expiratory maneuver.

A modification of the maneuver for the maximal expiratory flow volume (MEFV) curve was described recently to improve the rate of achieving the acceptability criteria of the American Thoracic Society. The maneuver allows the subject to relax in the later part of expiration. The present study was carried out to determine if the modified spirometry technique offered any advantages over the standard FVC maneuver in asthma patients with a wide range of airways obstruction. MEFV curves were obtained in seventy-two subjects with standard and modified procedures in a randomized, crossover design. The patients were divided into four groups depending on the degree of airways obstruction-normal spirometry, mild, moderate and severe airways obstruction. The spirometric parameters (FVC, FEV1, FEV/FVC ratio, FET, PEFR and F25-75) were compared in each group. The modified technique gave a higher FVC measurement especially in patients with moderate and severe airways obstruction along with increased FET. PEFR and FEV1 were not different between the techniques. FEV1/FVC ratio was significantly decreased in patients with moderate and severe airways obstruction. Both the techniques gave equally acceptable and reproducible results with similar variability for FEV1 and FVC. It was concluded that the modification of the standard FVC maneuver by allowing the subject to relax in the later part of expiration is advantageous as it yields a lower FEV1/FVC ratio without affecting the FEV1, has the same within-session variability and is less strenuous.

Interdependencia pulmonar: flujos espiratorios y vaciamiento pulmonar / Pulmonary interdependence: expiratory flow and lung emptying

En el ámbito de la kinesiología respiratoria (KTR), los análisis de la fase espiratoria han explorado los efectos de las intervenciones mecánicas sobre la movilización y el transporte de secreciones como productos claves de sus procesos. Desde los años 50 las técnicas de espiración forzada y de tos han sido dirigidas a favorecer el clearance mucoso bronquial y explicadas a través de principios básicos de la fisiología respiratoria, tales como la migración de las ondas de presión en las vías aéreas, la compresión dinámica y la generación de los puntos de choque; es decir, el fenómeno de la limitación del flujo espiratorio. Inicialmente, las terías del punto de igual presión y otras similares, propuestas en los años setenta por equipos de investigadores, permitieron explicar la limitación del flujo espiratorio y del efecto de compresión dinámica ocurridas durante la espiración a altos flujos en las vías aéreas centrales. Por supuesto, las acciones terapéuticas se sustentaron en tales ponencias. Posteriormente, con estudios auxiliares en los ochenta y noventa, se afinaron los conceptos precedentes y surgieron otros complementarios de los cuales importa destacar el modelo de la Interdependencia de los Flujos Espiratorios. Surge la ponencia de que si durante la inspiración el flujo se distribuye de manera heterogénea, durante la espiración también lo hará. Así, se logró profundizar en la existencia de zonas con diferentes secuencias de vaciado pulmonar evidente durante espiraciones a bajos flujos, dependiente de la gravedad y en el cual el aporte progresivo de las zonas superiores a la fracción espirada ocurrirá hacia el final de la espiración. De esta manera, las teorías de la constante de tiempo, de la velocidad de onda y de interdependencia cinemática y dinámica de los flujos espiratorios alcanzan la calidad de paradigmas para las acciones de la kinesiología sobre la mecánica de la respiración

Pruebas de función pulmonar en el niño / Lung function tests in children

Las pruebas de función pulmonar contribuyen al diagnóstico de la patología respiratoria, determinando el tipo de disfunción fisiológica, como por ejemplo, la obstrucción, la restricción, la hiperreactividad bronquial y la variabilidad de la vía aérea. Las pruebas que más se utilizan en niños mayores de 5 años son la espirometría, la curva flujo volumen, la provocación bronquial con ejercicio y con metacolina, y la flujometría. Este trabajo fue realizado con el objetivo de unificar criterios en la realización e interpretación de estas pruebas, por un grupo de 18 médicos representantes de los distintos centros dondo se realizan pruebas de función pulmonar en el niño en Chile. Se describen, para cada una de ellas, sus indicaciones, contraindicaciones, técnicas de realización e interpretación de los resultados